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Surface Finish Spacing Parameters

What are Surface Finish Spacing parameters?

Surface Finish Parameters Symbols
Spacing parameters RSm, WSm, PSm

RSm, WSm, PSm

RSm is the mean spacing between profile elements at the mean line, measured within the sampling length.

Rsm = 1/n ∑ i=ni=1 Si=[S1+S2+S3+ ------ +Sn] / n

Where n = number of peak spacings. WSm and PSm are the corresponding parameters from the waviness and primary profiles, respectively.


RHSC The high spot count is the number of complete profile peaks (within a sampling length) projecting above the mean line, or a line parallel with the mean line.


RPc (peak count) and is the number of peaks per unit distance that project through a selectable band centred about the mean line.

RPc= [Number of counts) / Assessment length (cm)] = Peasks / cm

In accordance with Amd 1, RPc is now calculated as

RPc= L / RSm

where L is the reference length (e.g. 1 cm or 1 inch).

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